


Primal Desire

by Widow_Spyder



Series: Sengen Week [1]
Category: Dr. STONE (Manga)
Genre: Animal Characteristics, Day 1, Fluff, Fluff and Smut, Implied Sexual Content, Kemonomimi, M/M, Sengen week, bottom Gen, sengen, top senku
Language: English
Status: Completed
Published: 2019-12-29
Updated: 2019-12-29
Packaged: 2021-02-19 05:15:43
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,708
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22005754
Author URL: https://archiveofourown.org/users/Widow_Spyder/pseuds/Widow_Spyder
Summary: The light that shone on him was just making him look even better, with his perfect eyes and body. Even his tail looked especially fluffy that morning.Wait, tail?
Relationships: Asagiri Gen/Ishigami Senkuu
Series: Sengen Week [1]
Series URL: https://archiveofourown.org/series/1584016
Comments: 12
Kudos: 273





	Primal Desire

Mornings in Ishigami village were pretty beautiful if you actually stopped what you were doing to notice them. On the rare occasion that Senku was up early after a nearly full night of brainstorming, he’d get to witness it, along with the other science kingdom citizens. Today was that day. 

Senku strolled towards the main area of the kingdom after having mistakenly woke up earlier than he wanted. Gen and Chrome had already left, so Senku figured he’d just join them instead of going back to sleep. 

The morning light was bright, making him squint and annoyingly go through the process of making sunglasses when he spotted the others, all gathered around Gen, who looked to be explaining something to them. 

Despite having just cursed at how bright and annoying the sun was to his sleep-deprived self, Senku couldn’t help but be secretly thankful for the view. 

Gen stood in the middle of everyone, holding a jar and waving his hands around like he was performing a magic trick. Elegant and smooth yet also manipulative and deceptive, much like the owner of said hands. Senku liked it more than he’d let himself accept. 

The light that shone on him was just making him look even better, with his perfect eyes and body. Even his tail looked especially fluffy that morning. 

_Wait, tail?_

Senku blinked, shook his head, and then blinked again, but the image never went away. There was still a tail and even ears attached to Gen’s body. In fact, after a brief look around, Senku realized everyone had some sort of animal characteristic added to their bodies. 

Chrome had bunny ears, Kohaku had a kangaroo tail, and even Suika had little puppy dog ears attached to her head. Kaseki also had dog ears and a tail, but they looked to be from a different breed than Suika’s. 

“I’m not sure how I feel about this.” He heard Kohaku say as he approached. 

“Come on, Kohaku-chan. Even you have to admit, it feels good to have your fur at least smooth and clean.” Gen responded with a hint of teasing in his voice. 

Kohaku inspected her tail, running her hands over it. “Maybe.” She muttered. 

“Suika likes how soft her ears feel now.” Suika excitedly stated while rubbing her own ears. 

“Ah! Senku-chan!” Gen turned towards Senku and gestured him to come closer to the group. “Care to join us?”

“What’s going on?” Senku found himself asking, still a little stunned at the complete change in human dynamics. 

“Gen made something called Arogon oil.” Chrome said, holding a bottle of his own towards Senku to take. 

“Argan oil.” Gen corrected. “You know, for hair?”

Suika excitedly ran around them. “It makes everything really soft!” 

“And it promotes hair growth!” Gen added. 

Kaseki huffed and grabbed the bottle out of Gen’s hand. “Does it now?” He asked. 

“Hehe, don’t go overboard old fossil.” Gen laughed while Kaseki scowled and dumped some in his hand. Senku did the same, letting a little bit of the oil run through his fingers. It was surprisingly smooth. 

“It’s impressive,” Senku said. 

“Isn’t it?” Gen smiled. “Although I don’t think it’ll work on your scales, Senku-chan.” Gen pointed towards Senku’s hands. “Sorry about that.”

Senku was about to respond when he suddenly stopped. Scales? Did he hear that right? Sure enough, when Senku looked down to inspect his own body, he found green scales running up his hands and arms. After a brief feel around his face, he also realized they covered half of his cheeks and neck. _There was no tail, though. Was that odd? Maybe he could transform like those awful cartoons Byakuya made him watch._ He didn’t have time to dwell on it as Gen’s voice cut off his observations. 

“Though it may work to make them shinier!” Gen happily announced with a light in his eyes that made Senku’s heart race. “Should we try it?”

Senku could only stare into those eyes and nod. “Sure, I guess.” 

“Great! I left some extra bottles in Chrome’s shed; let’s go.” Gen took Senku’s hand and pulled him in the right direction towards the science shed. 

Together they walked side by side until they reached the science shed and entered without so much as saying a word the whole time. From there, Gen shuffled around on the table before presenting a clay bottle of liquid. 

“Here it is!” Gen walked back towards Senku and taking one of his hands in his own. “Hold still now,” Gen said, rubbing the oil into his scales. It felt a little strange as the liquid soaked into his weird half-human, half snakeskin, but Senku couldn’t bring himself to notice for very long. His eyes were permanently stuck, staring at Gen’s face as he concentrated on getting Senku’s skin to absorb the oil. 

They stood close to each other, and Senku couldn’t help but feel his cheeks heat up. It took a minute, but Senku realized he liked looking at Gen’s face so close to his. The way his eyes were relaxed with his mouth open slightly, and his wolf ears perked up, had Senku feeling something he couldn’t describe. 

In a brief stiff of curiosity, Senku used his free hand to run through Gen’s hair. Suika was right; the oil definitely made the hair softer.

“Did you put some in?” Senku asked, rubbing over his scalp over and over. 

“Of course, I - agh!” Gen’s sentence was cut off as Senku stroked behind Gen’s ear, making him let out a breathy moan. Both science kingdom citizens sat stunned at the sudden reaction before Gen covered his mouth and blushed dark red. 

“That - that was nothing, I don’t know wh —” Senku didn’t let Gen finish as he stroked that area again, making Gen shut his lips tight to conceal the next onslaught of noises he was about to make.

Despite himself, Senku found his mouth quirking into a wicked grin. Quick as a whip, Senku maneuvered his hand out of Gen’s grip and reversed it to hold onto Gen’s arm instead. 

“Senku-chan?” Gen nervously squeaked. 

“Let’s switch now, mentalist,” Senku said, leaning further into Gen’s space and kissing the latter on the lips. At the same time, Senku used both hands to scratch behind Gen’s ears again, making him whine and moan into his mouth. He followed smoothly when Gen started falling to the floor as his legs suddenly became weak. 

From there, Senku sat up over Gen’s body, effectively trapping him there. Gen wasn’t paying enough attention to notice, though, as Senku didn’t stop stroking his fingers over his ears for a second. He did, however, notice when one hand stopped it’s incessant stroking on his ear to move down his neck and remove his overcoat by the collar. 

“Wait, no!” Gen protested, which fell on deaf ears as Senku was swiftly able to untie his obi and remove his yukata in seconds, leaving him only in his undershirt and pants. Then the same hand started lightly poking his skin and working under Gen’s shirt to ghost over his skin. 

Gen couldn’t tell whether he wanted to laugh at the ticklish feeling or moan at the pleasure as Senku changed locations rapidly, going from poking his side at his ribs to lightly tracing the skin just above the waistband of his pants. All the while, Senku kept scratching his ear and sucking his neck to mark the skin with bruises. 

He couldn’t help it. The primal urge to take this little wolf and make him his was strong. If Senku didn’t feel so drunk with power, he might’ve been shocked at how easily he slid into the role of dominance. Gen wasn’t helping either, with his cute little moans and failed attempts to keep quiet. 

“Don’t hold yourself back, Gen,” Senku said. “I want to hear you.” 

But Gen wasn’t having it. He shut his eyes tight and bit his bottom lip to stay silent. He wasn’t going to submit that easily. 

Senku sighed. “Fine, have it your way.” He whispered, leaning completely over Gen’s body to pin him down and run his hands over him again. 

Every reaction he got, Senku memorized it and played in that area until Gen was continuously turned to mush beneath him. But, true to Gen’s stubbornness, he hardly made a peep throughout the whole thing. Senku was getting impatient. He wanted to hear Gen say his name again. 

Using one hand, to keep up the stimulation in one known sensitive area, Senku used his other hand to explore and find new areas to make Gen squeal. After a while with no real results, Senku began to think he had found all of Gen’s sensitive areas. 

That is until he scratched underneath Gen’s tail near the base, which made the latter shriek and moan loudly. For a second, Senku was stunned, thinking he had hurt him, but after looking forward into Gen’s eyes and seeing nothing but pure desire, Senku continued with a smirk on his face. 

“Oh? Is this a weak spot that I’ve found?” Senku whispered, blowing hot air above Gen’s ear. 

“Ngk ~ Senku-ch - AH!” Gen yelled, not getting to finish as Senku scratched under his tail again. 

“There, just let your voice out.” Senku sucked Gen’s neck harder, scratching harshly behind one ear so Gen would tilt and expose more of his neck. 

“Noo,” Gen whined. 

“No, what?” Senku halted his process of marking Gen to look into his eyes, inches away from each other. “You want me to stop?” He genuinely asked though it’d take all the willpower he had left actually to do it. 

For a while, it was silent as they both stared at one another. Suddenly, Gen whined, the blush on his cheeks turning his face redder than ever. “Don - Don’t stop.” He whispered with half-lidded eyes and his mouth open in invitation. 

“As you wish, my mentalist.” Senku smiled, closing the distance and moving his lips onto Gen’s. 

“Haah!” Gen whimpered as Senku continuously teased him. His pants had shifted lower as Gen squirmed around and were now resting on his hip bones, effectively exposing his hips and lower stomach. Senku took the opportunity to move down lower and lightly kiss the exposed skin. “Senku-chan!” Gen nearly screamed as Senku’s hair tickled his skin, making him squirm. 

“Shh, I’ve got you.” 

“Lo - lower!” Gen squealed. “Touch lower.” 

_How needy,_ Senku thought. _But why deny him and myself now?_ Senku started sliding his hands lower and lower to fulfill both Gen’s wishes and his when he suddenly gasped and woke up.

————————

According to Senku’s inner counting habit, it took him 1 minute and 17 seconds to realize he had fully regained consciousness and another 21 seconds to realize that he had been dreaming a lewd dream with their resident mentalist.

Senku groaned and tried to roll over to forget that ever happened, but found the task to be difficult when he realized he was tangled in bedsheets with his mouth latched onto something soft. 

After a couple of embarrassing seconds of realization, Senku spit it out quickly and wiped the drool rolling down his chin. That something turned out to be a blanket that definitely didn’t belong to him if the purple shading was anything to go by.

Senku felt himself blush when he realized he’d been chewing Gen’s blanket in his sleep. The blush was then accompanied by a mini-stroke as he heard a small giggle above him and whipped his head up to stare into said mentalist’s eyes that he had dreamed about a few feet away from him.

“You better feel so lucky that you haven’t re-invented the camera yet.” Gen managed to say on the verge of laughter. 

Senku felt his cheeks redden, making him he turn away. “Shut up!” He yelled, making Gen double over and let out the giggles he had been containing. 

“Interesting dream, Senku-chan?” Gen asked fake, wiping tears from his eyes. 

Senku scowled. “None of your business, mentalist.”

“Hmm.” Gen hummed, choosing not to retort and instead stay silent. 

Senku frowned even harder than he thought possible as he tried to stand up and avoid the cunning magician he had nearly screwed in his dream. When he realized he couldn’t, Senku looked down at the cause and felt his blush brighten even redder on his face. 

The reason he couldn’t stand up was because he was death gripping Gen’s hand. Senku felt himself stiffen impossibly harder, as Gen stared up at him with the most innocent smile ever. _How had he not noticed that?_

“Something wrong, Senku-chan?” Gen practically sang as Senku let go and promptly buried his face into his pillow. 

“I hate you.” He muttered as Gen once again crashed into a fit of laughter. The sight of it was making Senku’s heart skip beats as his mind trailed back into his dream again. 

“Aww and why is that Sen—” Gen giggled but didn’t get to finish as Senku abruptly got up and crashed their lips together again. Gen would've reeled back in shock, had Senku not snaked his arm around his waist and prevented him from moving. Finally, Senku separated from the blushing mentalist to breathe. 

“What was —”

Senku didn’t let him finish again as he placed a hand on Gen’s chest, pushing him down and crawling on top of him. “You need to stop enticing me, mentalist. I can’t get any work done.”

“Huh?! — Mmph!” 

At this point, getting a sentence out was turning out to be useless as Senku kept kissing him to get him to shut up. Eventually, Gen let himself be taken, wrapping his arms around Senku’s neck and deepening their kiss. 

Senku smiled when their tongues intertwined, as he just as easily dominated the mentalist as he did in his dream. It made Senku wonder just how much his dream predicted to be right. To test his theory, Senku raised his hands and started smoothing through Gen’s hair, taking a piece and brushing it like a paintbrush over his earlobe. Senku could’ve laughed as Gen arched his back with a whine that broke off into a moan. _Same as in the dream,_ Senku grinned. 

“So, you’re sensitive behind the ears in reality too.” Senku licked Gen’s earlobe, earning another whine. “Does that mean you’re also sensitive here?” 

Senku asked, smoothing his fingers down Gen’s neck, making him shiver. He would’ve gone to more sensitive areas, but Gen’s clothes had been in the way. _Not for long,_ Senku thought, once again removing Gen’s clothing piece by complicated piece. 

Once down to his last layer, Senku went on the move to work Gen up again as he had in his dream. He lightly ran his fingers up and over Gen’s hips while sucking on his neck and occasionally connecting for another kiss. All the while, Gen was turning to putty beneath him, continuously moaning and even letting out a giggle as he poked around his ribs. 

Senku was about to shuck off the last layer of Gen’s outfit when a loud and embarrassed voice shouted, startling both into the ceiling. 

“Listen! I’m happy for you both. I really am! But there will be no acts like that in my shed!” Chrome shouted, red in the face and plugging his ears with his eyes shut. A second later, he practically jumped out of the science shed's door and slammed the door, leaving the two red-faced and still on top of each other.

“I think we may have ruined poor Chrome-chan’s innocence.” Gen laughed nervously. 

“Hmm. You know technically, the observatory belongs to me and not Chrome.” Senku gripped Gen’s chin and turned his head up to the ceiling and then back down to look at him. “Shall we continue up there.”

“Won’t we be needed?”

“Nah, Chrome will make sure no one goes searching for us.”

“How devious, Senku-chan.” Gen chuckled, making Senku smirk in satisfaction. 

“You like it.” 

Gen smiled and grabbed Senku’s collar to pull him close and connect their lips again. Senku felt giddy as he returned the gesture in full, moving his hands to grip Gen’s waist, so they were flush together. Once they separated, Gen moved over to whisper into Senku’s ear. “Maybe I do.”

**Author's Note:**

> Yay!! It's finally Sengen Week time!!! Don't know what that is? Here's a handy dandy link: https://www.tumblr.com/search/sengen+week
> 
> I have a tumblr too! @/ Widow-Spyder
> 
> Anyways, hope you enjoyed this one (though it's a bit different from what I normally write) and Thank You for reading this far!


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